Abstract: An immune proportional-integral-derivative(PID) controller based on the immune feedback mechanism is studied, which is applied in the process of the attitude control under all kinds of disturbances on sea to ensure the communication between the antenna and the satellite with high quality when the floating small-sized antenna tracks the target satellite. The various disturbances are studied and the immune PID controller based on the immune feedback mechanism and PID is designed to reject the disturbances on sea which affect the attitude control of the floating small-sized antenna seriously. Taking the azimuth control of the floating small-sized antenna as an example, MATLAB simulation and hardware-in-loop simulation validate the immune PID controller can realize the azimuth control under the disturbances, reject the influence of the disturbances and ensure the communication with high qualitybetween the floating small-sized anten-na and the target satellite.